The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Peripheral devices communicate with a host (e.g., a computer, a television, and a digital video recorder). Peripheral devices are separate from the host, typically operationally dependent upon the host, and supplement capabilities of the host. Examples of peripheral devices are a memory drive, a printer, a projector, etc. Peripheral devices include, for example, one or more control modules, hard disk drive(s), a printer mechanism, a projection lamp circuit, and a scanner lamp circuit.
A peripheral device typically includes a first power switch (sometimes referred to as a main power switch) for manual power ON and OFF of the peripheral device. The first power switch has a CLOSED (or ON) state and an OPEN (or OFF) state. The peripheral device is deactivated when the first power switch is transitioned to the OFF state. All components including control modules and peripheral circuits of the peripheral device are powered down when the peripheral device is deactivated. The peripheral device is deactivated without flushing volatile memory and/or cache of the peripheral device to non-volatile memory when the first switch is transitioned to the OFF state.
A peripheral device may also include a soft power switch having an OPEN and CLOSED state. The soft power switch is also manually operated and transitions the peripheral device between power ON and power OFF modes. In the power ON mode, the peripheral device is fully powered up and is in communication with the host. Components of the peripheral device including control modules and peripheral circuits are powered down when transitioning to the power OFF mode. The peripheral device transitions from the power ON mode to the power OFF mode when the soft power switch is transitioned from a CLOSED state to an OPEN state. The peripheral device flushes volatile memory and/or cache to non-volatile memory when transitioning from the power ON mode to the power OFF mode and the soft power switch is in the OPEN state.
In addition to having a power ON mode and a power OFF mode, peripheral devices may operate in a standby mode. For example, a storage device may be connected to a host and receive a standby request signal from the host. The storage device may power down certain high-power components, such as hard disk drive(s) to conserve energy. Other components, such as control modules and corresponding integrated circuits, regulators, cooling fans, etc. remain powered up.
A control module and corresponding integrated circuit of the storage device is maintained in a powered up state to receive communication signals from the host. This allows the host to reactivate the storage device from the standby mode to a fully powered up state (or power ON mode) when access to the storage device is needed. Because the control module is maintained in a powered up state, a regulator and cooling fan are also maintained in a powered up state. The regulator provides and regulates power to the control module and the cooling fan. The cooling fan maintains temperature of the storage device within a predetermined range.